London, UK to Rovaniemi is an approximately 6.5-hour flight. You can also do a combination of car and train; or do a combination of car and ferry. The time zone difference moving from Greenwich Mean Time (GMT) to Eastern European Time (EET) is 2 hours. Traveling from London in December, expect Rovaniemi to be much colder, temps between -6°C and -13°C. Wrap up your sightseeing on the 28th (Sat) early enough to travel back home.